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Ramola RC, Prasad M, Sahoo SK, Tokonami S. Estimation of radiation dose due to thoron and progeny inhalation in high background natural radiation area of Odisha, India. RADIATION PROTECTION DOSIMETRY 2023; 199:2179-2182. [PMID: 37934988 DOI: 10.1093/rpd/ncad173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/23/2023] [Accepted: 05/18/2023] [Indexed: 11/09/2023]
Abstract
Results of the preliminary measurements of indoor radon, thoron and progeny concentrations showed very high values of thoron concentrations in the eastern coastal region of Odisha, India. Therefore, measurements of thoron and its progeny concentrations were extended to a larger number of houses in this area for the assessment of the radiation dose received by the public. The measured values of thoron concentrations were used for the calculation of annual effective doses. The estimated values of the annual effective dose due to thoron exposure were observed in the range of 0.2-14.7 mSv. The estimated radiation doses responsible for thoron exposure were observed considerably high in the region. The results obtained are compared with those obtained in other studies performed so far in the study area and a review of different studies involving different measurement techniques is presented in the paper. The results of this study support the preliminary studies showing high values of thoron levels in the study area.
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Affiliation(s)
- Rakesh C Ramola
- Department of Physics, H.N.B. Garhwal University, Badshahi Thaul Campus, Tehri Garhwal 249199, India
| | - Mukesh Prasad
- Chitkara University School of Engineering and Technology, Chitkara University, Solan, Himachal Pradesh 174103, India
| | - Sarata K Sahoo
- National Institute of Radiological Sciences, National Institute of Quantum Sciences and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki 036-8564, Japan
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Veerasamy N, Kasar S, Murugan R, Inoue K, Natarajan T, Chand Ramola R, Fukushi M, Kumar Sahoo S. 234U/ 238U disequilibrium and 235U/ 238U ratios measured using MC-ICP-MS in natural high background radiation area soils to understand the fate of uranium. CHEMOSPHERE 2023; 323:138217. [PMID: 36849023 DOI: 10.1016/j.chemosphere.2023.138217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/11/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
The Chhatrapur-Gopalpur coastal area in Odisha, India is a well-known natural high background radiation (HBRA) area due to the abundance of monazite (a thorium bearing radioactive mineral) in beach sands and soils. Recent studies on Chhatrapur-Gopalpur HBRA groundwater have reported high concentrations of uranium and its decay products. Therefore, the soils of the Chhatrapur-Gopalpur HBRA are reasonably suspected as the sources of these high uranium concentrations in groundwater. In this report, first the uranium concentrations in soil samples were measured using inductively coupled plasma mass spectrometry (ICP-MS) and they were found to range from 0.61 ± 0.01 to 38.59 ± 0.16 mg kg-1. Next, the 234U/238U and 235U/238U isotope ratios were measured to establish a baseline for the first time in Chhatrapur-Gopalpur HBRA soil. Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) was used for measurement of these isotope ratios. The 235U/238U ratio was observed to be the normal terrestrial value. The 234U/238U activity ratio, was calculated to understand the secular equilibrium between 234U and 238U in soil and it varied from 0.959 to 1.070. To understand the dynamics of uranium in HBRA soil, physico-chemical characteristics of soil were correlated with uranium isotope ratios and this correlation of 234U/238U activity ratio indicated the leaching of 234U from Odisha HBRA soil.
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Affiliation(s)
- Nimelan Veerasamy
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan; National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Sharayu Kasar
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Rajamanickam Murugan
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Kazumasa Inoue
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
| | - Thennaarassan Natarajan
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan; National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Rakesh Chand Ramola
- H.N.B. Garhwal University, Badshahi Thaul Campus, Tehri Garhwal, 249 199, India
| | - Masahiro Fukushi
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
| | - Sarata Kumar Sahoo
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
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Kaushal A, Joshi M, Sarin A, Sharma N. Dosimetry of indoor alpha flux belonging to seasonal radon, thoron and their EECs. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:119. [PMID: 35072797 DOI: 10.1007/s10661-021-09746-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Radon (222Rn) and thoron (220Rn) are ubiquitous radioactive noble gases present in the earth's crust. The source term for these gases includes soil and building materials as well. The radiological impact of radon/thoron gases and their decay products on human life is a matter of concern and has been given due attention in research and policy. The present study aims to measure and quantify residential radon/thoron gas and the decay product's concentration and to discuss the associated interpretations for Ludhiana district of Punjab, India. Passive measurement techniques employing a single-entry pinhole dosimeter for gases and direct progeny sensors for the decay product's concentration have been used in this work. The obtained data from these measurements have been analysed using appropriate statistical techniques. The variations have been linked with the changes in the ventilation conditions, building material, room type and altitude. A higher concentration of radon and thoron gas was observed in the winter season for the study region. It was estimated that the contribution of radon and thoron decay products towards the annual average inhalation dose is 75% and 25%, respectively.
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Affiliation(s)
- Anjali Kaushal
- Department of Physical Sciences, I.K.G. Punjab Technical University, Kapurthala, 144601, Punjab, India.
- Department of Physics, D.A.V. College, Jalandhar, 144008, Punjab, India.
| | - Manish Joshi
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Amit Sarin
- Department of Physical Sciences, I.K.G. Punjab Technical University, Amritsar Campus, Amritsar, 143105, Punjab, India
| | - Navjeet Sharma
- Department of Physics, D.A.V. College, Jalandhar, 144008, Punjab, India
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Sun C, Wang Y, Zhang L, Wang H, Guo Q, Xiao D, Liang J, Wang S. FIELD MEASUREMENT OF THE UNATTACHED FRACTION AND ACTIVITY CONCENTRATION RATIO OF RADON PROGENY IN TYPICAL DWELLINGS. RADIATION PROTECTION DOSIMETRY 2021; 197:125-134. [PMID: 34850219 DOI: 10.1093/rpd/ncab166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
The unattached fraction (fp) and activity concentration ratio of radon progeny (${\boldsymbol C}_{{}{}^{\bf 218}\bf{Po}}:{\boldsymbol C}_{{}{}^{\bf 214}\bf{Pb}}:{\boldsymbol C}_{{}{}^{\bf 214}\bf{Bi}}$) are important for radon exposure dose evaluation. For getting these characteristic parameters in dwellings, a series of field measurement was carried out. For comparison, a semi-continuous measurement was carried out in an office room and outdoors. Results show that the average fp is 4.5% ± 2.2% and 3.8% ± 1.7% in city dwellings and in rural dwellings, respectively. The average activity concentration ratios are 1:0.94:0.70 for radon progeny and 1:0.07:0.06 for unattached radon progeny in city dwellings, while those in rural dwellings are 1:0.88:0.66 and 1:0.09:0.07. The average values of fp are 5.1% ± 0.9% and 5.4% ± 3.1% in the office room and in outdoors without significant difference. The average activity concentration ratios are 1:0.88:0.77 for radon progeny and 1:0.11:0.11 for unattached radon progeny in outdoors.
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Ramola RC, Prasad M. Significance of thoron measurements in indoor environment. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 225:106453. [PMID: 33120031 DOI: 10.1016/j.jenvrad.2020.106453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/17/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
Radon, 222Rn, is the major contributor to natural radiation in human environment. The exposure of high radon is known as one of the causative factors of lung cancer. Though thoron, 220Rn, has been a matter of study in atmospheric science, but it was often neglected compared to radon. It was considered that the amount of thoron in the environment is less than that of radon. However, recent studies show that thoron and its progeny sometime contribute significantly to the radiation dose in residential buildings. A review of methodologies, measurement protocols and concepts used in various thoron measurement surveys performed in India is presented in this paper. The results of measurements of thoron and its progeny, carried out in the Himalayan region and in the high background radiation area of the south-eastern coast of Odisha, India are also presented. The results obtained using various thoron measurements techniques and the resulting doses to the general public are discussed in details.
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Affiliation(s)
- R C Ramola
- Department of Physics, H.N.B. Garhwal University, Badshahi Thaul Campus, Tehri Garhwal, 249 199, India.
| | - Mukesh Prasad
- Department of Physics, H.N.B. Garhwal University, Badshahi Thaul Campus, Tehri Garhwal, 249 199, India
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Tokonami S. Characteristics of Thoron ( 220Rn) and Its Progeny in the Indoor Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E8769. [PMID: 33255858 PMCID: PMC7728306 DOI: 10.3390/ijerph17238769] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 01/14/2023]
Abstract
The present paper outlines characteristics of thoron and its progeny in the indoor environment. Since the half-life of thoron (220Rn) is very short (55.6 s), its behavior is quite different from the isotope radon (222Rn, half-life 3.8 days) in the environment. Analyses of radon and lung cancer risk have revealed a clearly positive relationship in epidemiological studies among miners and residents. However, there is no epidemiological evidence for thoron exposure causing lung cancer risk. In contrast to this, a dosimetric approach has been approved in the International Commission on Radiological Protection (ICRP) Publication 137, from which new dose conversion factors for radon and thoron progenies can be obtained. They are given as 16.8 and 107 nSv (Bq m-3 h)-1, respectively. It implies that even a small quantity of thoron progeny will induce higher radiation exposure compared to radon. Thus, an interest in thoron exposure is increasing among the relevant scientific communities. As measurement technologies for thoron and its progeny have been developed, they are now readily available. This paper reviews measurement technologies, activity levels, dosimetry and resulting doses. Although thoron has been underestimated in the past, recent findings have revealed that reassessment of risks due to radon exposure may need to take the presence of thoron and its progeny into account.
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Affiliation(s)
- Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki 036-8564, Aomori, Japan
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Kumar A, Singh P, Agarwal T, Joshi M, Semwal P, Singh K, Pathak PP, Ramola RC. Statistical inferences from measured data on concentrations of naturally occurring radon, thoron, and decay products in Kumaun Himalayan belt. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:40229-40243. [PMID: 32661978 DOI: 10.1007/s11356-020-09920-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 06/29/2020] [Indexed: 06/11/2023]
Abstract
Regional averages of radon, thoron, and associated decay product concentration are reported to be higher than their respective global averages in recent studies conducted in Indian Himalayan belt. The present study explores another region in Indian Himalayan belt by conducting measurements of radon, thoron, and decay product's activity concentration in 92 dwellings of Bageshwar district. The year-long measurements were performed in all 3 seasons distinguishing dwellings as per their construction material. The average radon and thoron concentration for the study region was measured as 57 Bq/m3 and 66 Bq/m3, respectively. Analysis of the measured data in terms of seasonal effects and construction material led to well established inferences, i.e., higher concentration for mud houses and for winter season. In addition, the present study focuses on lesser probed statistical inferences. One of them is related to the appropriateness of frequency distribution function for the measured data and other dwells upon the correlation analysis of inter-related factors for high concentration cases. Three distribution functions (Lognormal, Weibull, and Gamma) were found to be following the trend of frequency distribution curve of the measured data. For mud houses in winter season, variations of radon/thoron concentration were attempted to correlate with mass/surface exhalation rate, emanation rate, and source term content. More than 80% of the dwellings of the study region were found to have gas and decay product's concentration levels, higher than the respective global average values. However, these values were mostly within the reference levels for residential environments. Nevertheless, this region requires further studies to pinpoint the causes for elevated levels and suggest simple remedial modifications if required.
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Affiliation(s)
- Ankur Kumar
- Department of Physics, Gurukula Kangri Vishwavidyalaya Haridwar, Haridwar, Uttarakhand, 249406, India.
| | | | - Tarun Agarwal
- Radiological physics and advisory division, Bhabha Atomic Research Center, Mumbai, India
| | - Manish Joshi
- Radiological physics and advisory division, Bhabha Atomic Research Center, Mumbai, India
| | - Poonam Semwal
- Department of Physics, Govt. PG College New Tehri, New Tehri, Uttarakhand, India
| | - Kuldeep Singh
- Department of Physics, Govt. PG College New Tehri, New Tehri, Uttarakhand, India
| | - Parmanad Prakash Pathak
- Department of Physics, Gurukula Kangri Vishwavidyalaya Haridwar, Haridwar, Uttarakhand, 249406, India
| | - Rakesh Chand Ramola
- Department of Physics, HNBGU Badshahithaul New Tehri, New Tehri, Uttarakhand, India
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Omori Y, Hosoda M, Takahashi F, Sanada T, Hirao S, Ono K, Furukawa M. Japanese population dose from natural radiation. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:R99-R140. [PMID: 32031989 DOI: 10.1088/1361-6498/ab73b1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The radiation doses from natural radiation sources in Japan are reviewed using the latest knowledge. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation, and ingestion as natural sources. In this paper, the total annual effective dose from cosmic-ray exposure is evaluated as 0.29 mSv. The arithmetic mean of the annual effective dose from external exposure to terrestrial radiation is 0.33 mSv for the Japanese population using the data of nationwide surveys by the National Institute of Radiological Sciences. Previously in Japan, although three different groups have conducted nationwide indoor radon surveys using passive-type radon monitors, to date only the Japan Chemical Analysis Center (JCAC) has performed a nationwide radon survey using a unified method for radon measurements conducted indoor, outdoor, and in the workplace. Consequently, the JCAC results are used for the annual effective dose from radon and that for radon inhalation is estimated as 0.50 mSv using a current dose conversion factor. In this paper, UNSCEAR values are used for the mean indoor and outdoor thoron-progeny concentrations, and the annual effective dose from thoron is reported as 0.09 mSv. Thus, the annual effective dose from radon and thoron inhalation is 0.59 mSv. From a JCAC large-scale survey of foodstuffs, the committed effective dose from the main radionuclides in dietary intake is 0.99 mSv. Finally, the Japanese population dose from natural radiation is given as 2.2 mSv, which is similar to the reported global average of 2.4 mSv.
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Affiliation(s)
- Yasutaka Omori
- Ad hoc Committee of Japanese Population Dose Estimation of Japan Health Physics Society, Yoshimatsu Buid. 3F, 3-7-2 Shimbashi, Minato-ku, Tokyo 105-0004, Japan. Department of Radiation Physics and Chemistry, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan
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Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17093178. [PMID: 32370255 PMCID: PMC7246621 DOI: 10.3390/ijerph17093178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/22/2020] [Accepted: 04/30/2020] [Indexed: 11/29/2022]
Abstract
Air exchange through a porous medium depends partly on a pressure gradient induced in it, i.e., air-flow conditions of the outer air. Consequently, response of diffusion-type detectors to radon and thoron may vary with air-flow conditions surrounding the detectors. This effect may be significant for thoron measurement because thoron has a shorter half-life than radon. The present study examined response of diffusion-type detectors (RADUETs and one AlphaGUARD) to thoron with respect to wind speed using a thoron calibration chamber. Response of RADUETs to thoron increased with wind speed. Response of the AlphaGUARD increased with wind speed, but it became constant at a high wind speed. Different response trends to thoron between the RADUETs and the AlphaGUARD could be qualitatively explained by flow states induced by the pressure gradient in the filter or the sponge of these detectors. For RADUETs, laminar (Darcy) flow was induced in the sponge in the examined wind speed range, which meant that thoron entry into the detector increased with wind speed. For the AlphaGUARD, laminar flow was induced in the filter in the low wind speed range, whereas flow was changed to turbulent (non-Darcy) flow at a high wind speed for which thoron entry into the detector did not depend on wind speed.
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Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030974. [PMID: 32033235 PMCID: PMC7036855 DOI: 10.3390/ijerph17030974] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 11/27/2022]
Abstract
Thoron interference in radon measurements using passive diffusion radon detectors/monitors is a crucial problem when it comes to assessing the internal exposure to radon precisely. The present study reported, as one of the potential factors, the effects of air flow conditions on changes in thoron interference. Rates of thoron infiltration (as thoron interference) into the diffusion chamber of the monitor were evaluated. The temporal variation was obtained based on measurements of the underfloor space of a Japanese wooden dwelling using a diffusion-type radon monitor, a reference radon monitor which was not affected by thoron interference, and a thoron monitor. The thoron infiltration rate for the diffusion-type monitor varied from 0% to 20%. In particular, it appeared to increase when ventilation of the underfloor space air was forced. The variable thoron infiltration rate, with respect to ventilation strength, implied that not only a diffusive process, but also an advective process, played a major role in air exchange between the diffusion chamber of the monitor and the outer air. When an exposure room is characterized by the frequent variation in air ventilation, a variable thoron response is considered to occur in radon–thoron discriminative detectors, in which only diffusive entry is employed as a mechanism for the discrimination of radon and thoron.
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Omori Y, Sorimachi A, Gun-Aajav M, Enkhgerel N, Oyunbolor G, Palam E, Yamada C. ELEVATION OF GAMMA DOSE RATE BY CONSTRUCTION OF THE ASIAN HIGHWAY 3 (AH3) BETWEEN ULAANBAATAR AND SAINSHAND, MONGOLIA. RADIATION PROTECTION DOSIMETRY 2019; 184:127-134. [PMID: 30307569 DOI: 10.1093/rpd/ncy173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 09/07/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
The present study aimed at examining changes of gamma radiation level associated with road construction in Mongolia. A car-borne survey of gamma dose rate was made for a paved, ~450-km long part of the Asian Highway 3 between Ulaanbaatar and Sainshand. The gamma dose rates ranged from 48 to 173 nGy/h. Elevation of the gamma dose rates was observed only on a 86-km long segment of the survey route which was newly constructed from 2011 to 2013. The gamma dose rates over the newer paved segment were twice as high as those over the bare dirt surface alongside it. Outdoor measurements of gamma-ray pulse height distributions also indicated an abundance of natural radionuclides, especially 232Th-series elements in road materials. These findings suggest that the gamma dose rates were elevated by introduction of road materials containing large amounts of natural radionuclides.
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Affiliation(s)
- Yasutaka Omori
- Department of Radiation Physics and Chemistry, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Japan
| | - Atsuyuki Sorimachi
- Department of Radiation Physics and Chemistry, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Japan
| | - Manlaijav Gun-Aajav
- The Executive Office of the Nuclear Energy Commission, Uildverchid Street 2, Khan Uul District, Ulaanbaatar, Mongolia
| | - Nyamdavaa Enkhgerel
- The Executive Office of the Nuclear Energy Commission, Uildverchid Street 2, Khan Uul District, Ulaanbaatar, Mongolia
| | - Galnemekh Oyunbolor
- The Executive Office of the Nuclear Energy Commission, Uildverchid Street 2, Khan Uul District, Ulaanbaatar, Mongolia
| | - Enkhtuya Palam
- National Center for Public Health, Ministry of Health, 17 Peace Avenue, Ulaanbaatar, Mongolia
| | - Chieri Yamada
- Department of Public Health Nursing for International Radiation Exposure, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Japan
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Semwal P, Agarwal TK, Singh K, Joshi M, Gusain GS, Sahoo BK, Ramola RC. Indoor inhalation dose assessment for thoron-rich regions of Indian Himalayan belt. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:4855-4866. [PMID: 30569360 DOI: 10.1007/s11356-018-3891-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
222Rn, 220Rn, and their decay products are significant contributors to background radiation dose. Their concentration level, pertaining exposure, and consequent dose are prime concerns in indoor environments. The present study was performed in 101 dwellings of different villages of Almora district situated in Kumaun hills of Indian Himalayan belt. Measurement of gases and decay products were made in three different types of dwellings (i.e., mud, cemented, and stone with plaster) in three seasons (winter, summer, and rainy). Concentration values for 222Rn and EERC were found to be varying in the order of winter > summer > rainy while obtained least in rainy season for the case of 220Rn and EETC. Concentration values for 222Rn and EERC were found to be lesser for cemented houses. Relative standard deviation of concentration values was found to be higher for the rainy season. Yearly averaged concentration values for 222Rn, EERC, 220Rn, and EETC were noted to be higher than the global averages but comparable to some Indian studies. Annual inhalation dose due to 222Rn, 220Rn, and their progeny was found to be 0.55-4.71 mSv/year with an average value of 2.36 ± 0.83 mSv/year. These values were measured for the first time in the study area and provide a link for future studies in the dwellings representing higher concentration values.
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Affiliation(s)
- Poonam Semwal
- Department of Physics, Govt. P.G. College, New Tehri, Tehri Garhwal, 249001, India
| | - Tarun Kumar Agarwal
- Radiological Physics and Advisory Division, Bhabha Atomic Research Center, Mumbai, 400094, India
| | - Kuldeep Singh
- Department of Physics, Govt. P.G. College, New Tehri, Tehri Garhwal, 249001, India
| | - Manish Joshi
- Radiological Physics and Advisory Division, Bhabha Atomic Research Center, Mumbai, 400094, India.
| | - Gurupad Singh Gusain
- Department of Physics, Govt. P.G. College, New Tehri, Tehri Garhwal, 249001, India
| | - Bijay Kumar Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Center, Mumbai, 400094, India
| | - Rakesh Chand Ramola
- Department of Physics, HNB, Garhwal University, BadshahiThaul Campus, Tehri Garhwal, 249199, India
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Salama E, Ehab M, Rühm W. Radon and thoron concentrations inside ancient Egyptian tombs at Saqqara region: Time-resolved and seasonal variation measurements. NUCLEAR ENGINEERING AND TECHNOLOGY 2018. [DOI: 10.1016/j.net.2018.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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He Z, Xiao D, Lv L, Zhou Q, Shan J, Qiu S, Wu X. Controlling 212Bi to 212Pb activity concentration ratio in thoron chambers. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:77-83. [PMID: 28797795 DOI: 10.1016/j.jenvrad.2017.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
It is necessary to establish a reference atmosphere in a thoron chamber containing various ratios of 212Bi to 212Pb activity concentrations (C(212Bi)/C(212Pb)) to simulate typical environmental conditions (e.g., indoor or underground atmospheres). In this study, a novel method was developed for establishing and controlling C(212Bi)/C(212Pb) in a thoron chamber system based on an aging chamber and air recirculation loops which alter the ventilation rate. The effects of main factors on the C(212Bi)/C(212Pb) were explored, and a steady-state theoretical model was derived to calculate the ratio. The results show that the C(212Bi)/C(212Pb) inside the chamber is mainly dependent on ventilation rate. Ratios ranging from 0.33 to 0.83 are available under various ventilation. The stability coefficient of the ratios is better than 7%. The experimental results are close to the theoretical calculated results, which indicates that the model can serve as a guideline for the quantitative control of C(212Bi)/C(212Pb).
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Affiliation(s)
- Zhengzhong He
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
| | - Detao Xiao
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China.
| | - Lidan Lv
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
| | - Qingzhi Zhou
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
| | - Jian Shan
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
| | - Shoukang Qiu
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
| | - Xijun Wu
- School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China
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15
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He Z, Xiao D, Lv L, Zhou Q, Wu X, Shan J. Stable control of thoron progeny concentration in a thoron chamber for calibration of active sampling monitors. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Omori Y, Tokonami S, Sahoo SK, Ishikawa T, Sorimachi A, Hosoda M, Kudo H, Pornnumpa C, Nair RRK, Jayalekshmi PA, Sebastian P, Akiba S. Radiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:111-126. [PMID: 28002043 DOI: 10.1088/1361-6498/37/1/111] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In order to evaluate internal exposure to radon and thoron, concentrations for radon, thoron, and thoron progeny were measured for 259 dwellings located in high background radiation areas (HBRAs, outdoor external dose: 3-5 mGy y-1) and low background radiation areas (control areas, outdoor external dose: 1 mGy y-1) in Karunagappally Taluk, Kerala, India. The measurements were conducted using passive-type radon-thoron detectors and thoron progeny detectors over two six-month measurement periods from June 2010 to June 2011. The results showed no major differences in radon and thoron progeny concentrations between the HBRAs and the control areas. The geometric mean of the annual effective dose due to radon and thoron was calculated as 0.10 and 0.44 mSv, respectively. The doses were small, but not negligible compared with the external dose in the two areas.
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Affiliation(s)
- Yasutaka Omori
- Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. Current address: Department of Radiation Physics and Chemistry, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan
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17
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Meisenberg O, Mishra R, Joshi M, Gierl S, Rout R, Guo L, Agarwal T, Kanse S, Irlinger J, Sapra BK, Tschiersch J. Radon and thoron inhalation doses in dwellings with earthen architecture: Comparison of measurement methods. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:1855-1862. [PMID: 27939079 DOI: 10.1016/j.scitotenv.2016.11.170] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/04/2016] [Accepted: 11/24/2016] [Indexed: 06/06/2023]
Abstract
The radioactive noble gas radon (222Rn) and its decay products have been considered a health risk in the indoor environment for many years because of their contribution to the radiation dose of the lungs. The radioisotope thoron (220Rn) and its decay products came into focus of being a health risk only recently. The reason for this is its short half-life, so only building material can become a significant source for indoor thoron. In this study, dwellings with earthen architecture were investigated with different independent measurement techniques in order to determine appropriate methods for reliable dose assessment of the dwellers. While for radon dose assessment, radon gas measurement and the assumption of a common indoor equilibrium factor often are sufficient, thoron gas has proven to be an unreliable surrogate for a direct measurement of thoron decay products. Active/time-resolved but also passive/integrating measurements of the total concentration of thoron decay products demonstrated being precise and efficient methods for determining the exposure and inhalation dose from thoron and its decay products. Exhalation rate measurements are a useful method for a rough dose estimate only if the exhalation rate is homogeneous throughout the house. Before the construction of a building in-vitro exhalation rate measurements on the building material can yield information about the exposure that is to be expected. Determining the unattached fraction of radon decay products and even more of thoron decay products leads to only a slightly better precision; this confirms the relative unimportance of the unattached thoron decay products due to their low concentration. The results of this study thereby give advice on the proper measurement method in similar exposure situations.
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Affiliation(s)
- Oliver Meisenberg
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
| | - Rosaline Mishra
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India.
| | - Manish Joshi
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India
| | - Stefanie Gierl
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Rajeswari Rout
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India
| | - Lu Guo
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Tarun Agarwal
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India
| | - Sandeep Kanse
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India
| | - Josef Irlinger
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Balvinder K Sapra
- Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai 400 085, India.
| | - Jochen Tschiersch
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
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18
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Fijałkowska-Lichwa L. Extremely high radon activity concentration in two adits of the abandoned uranium mine 'Podgórze' in Kowary (Sudety Mts., Poland). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 165:13-23. [PMID: 27573759 DOI: 10.1016/j.jenvrad.2016.08.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/12/2016] [Accepted: 08/19/2016] [Indexed: 06/06/2023]
Abstract
Measurements of radon activity concentration were conducted for a period of 6 months, from April to September 2011, in the air of two adits constituting part of the disused uranium mine 'Podgórze' in Kowary. Adits no. 19 and 19a in Kowary had been chosen owing to the occurrence within them of the highest documented radon concentrations in Poland, With levels higher than a million Bq m-3. The main goal of this study was to characterize the level of 222Rn activity concentration registered in selected workings of this underground space, investigate 222Rn changes and their characteristics over selected periods of time (an hour, a day, a month, six months) and determine the effective doses, which provided the basis for estimating the risk of exposure to increased ionizing radiation for employees and visitors to the mine. The highest values of 222Rn activity concentration inside the adits occurred at the time when visitors, guides and other members of the staff were present there. The recorded values of radon activity concentration, regardless of the time and the month when the measurement was performed, remained at an average level of 350-400 kBq m-3. These values were far above the limit of 1.5 kBq·m-3 recommended by international guidelines. The maximum values ranged from 800 to more than 1000 kBq·m-3. Radon activity concentration changes occurred only in periods determined by 7-h cycles of connecting and disconnecting the mechanical ventilation. For about 7 h after activating the ventilation system, between 7 a. m. and 2 p. m., and after closing the adit, between 7 p. m. and 2 a. m., 222Rn activity concentrations decreased to levels even as low as 100 kBq·m-3. However, as early as 3-4 h after disconnecting the ventilation system, there was a sharp rise in the values of 222Rn activity concentration, to the level higher than 800 kBq·m-3. The risk of receiving a radiation dose higher than the national standard of 1 mSv/year by members of the public occurred as soon as after spending 1 h inside the workings. The minimum monthly effective radiation dose received by every employee in the tourist adit no. 19 in Kowary was higher than 1/5 (4 mSv) of the annual effective dose allowed by Polish law (20 mSv/year). In the non-tourist adit no. 19, the minimum monthly radiation dose was more than 3 times as high as the allowed value of 4 mSv. Due to the highly disturbing and unfavourable, from a radiological protection point of view, conditions inside the disused uranium mine 'Podgórze' in Kowary, the mine manager decided to increase the efficiency of the designed mechanical ventilation system and launch measurements of radon activity concentration in the workplace.
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Affiliation(s)
- Lidia Fijałkowska-Lichwa
- Wrocław University of Science and Technology, Faculty of Civil Engineering, Division of Geotechnics, Hydrotechnics, Underground Construction and Hydrological Engineering, 50-370 Wrocław, Wybrzeże S. Wyspiańskiego 27, Poland.
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19
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Fijałkowska-Lichwa L, Przylibski TA. First radon measurements and occupational exposure assessments in underground geodynamic laboratory the Polish Academy of Sciences Space Research Centre in Książ Castle (SW Poland). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 165:253-269. [PMID: 27814500 DOI: 10.1016/j.jenvrad.2016.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/15/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
The article presents the results of the first radon activity concentration measurements conducted continuously between 17th May 2014 and 16th May 2015 in the underground geodynamic laboratory of the Polish Academy of Sciences Space Research Centre in Książ. The data were registered with the use of three Polish semiconductor SRDN-3 detectors located the closest (SRDN-3 No. 6) to and the furthest (SRDN-3 No. 3) from the facility entrance, and in the fault zone (SRDN-3 No. 4). The study was conducted to characterize the radon behaviour and check it possibility to use with reference to long- and short-term variations of radon activity concentration observed in sedimentary rocks strongly fractured and intersected by systems of multiple faults, for integrated comparative assessments of changes in local orogen kinetics. The values of radon activity concentration in the underground geodynamic laboratory of the Polish Academy of Sciences (PAN) Space Research Centre in Książ undergo changes of a distinctly seasonal character. The highest values of radon activity concentration are recorded from late spring (May/June) to early autumn (October), and the lowest - from November to April. Radon activity concentrations varied depending on the location of measurement points. Between late spring and autumn they ranged from 800 Bq·m-3 to 1200 Bq·m-3, and even 3200 Bq·m-3 in the fault zone. Between November and April, values of radon activity concentration are lower, ranging from 500 Bq·m-3 to 1000 Bq·m-3 and 2700 Bq·m-3 in the fault zone. The values of radon activity concentration recorded in the studied facility did not undergo short-term changes in either the whole annual measuring cycle or any of its months. Effective doses received by people staying in the underground laboratory range from 0.001 mSv/h to 0.012 mSv/h. The mean annual effective dose, depending on the measurement site, equals 1 or is slightly higher than 10 mSv/year, while the maximum dose exceeds 20 mSv/year. The estimated annual effective doses are comparable to the standard value of 20 mSv/year defined by Polish law for people employed in the conditions of radiation exposure. They are also in the range of annual effective dose value (8 mSv/year) recommended in workplaces by International Commission on Radiation Protection.
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Affiliation(s)
- Lidia Fijałkowska-Lichwa
- Wrocław University of Science and Technology, Faculty of Civil Engineering, Division of Geotechnics, Hydrotechnics, Underground Construction and Hydrological Engineering, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Tadeusz A Przylibski
- Wrocław University of Science and Technology, Faculty of Geoengineering, Mining and Geology, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław, Poland.
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20
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Hosoda M, Kudo H, Iwaoka K, Yamada R, Suzuki T, Tamakuma Y, Tokonami S. Characteristic of thoron ( 220Rn) in environment. Appl Radiat Isot 2016; 120:7-10. [PMID: 27894046 DOI: 10.1016/j.apradiso.2016.11.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/21/2016] [Accepted: 11/15/2016] [Indexed: 10/20/2022]
Abstract
This paper describes importance of 220Rn (hereafter thoron) progeny measurement for the dose estimation. Although the spatial distribution of thoron activity concentration strongly depends on the distance from wall surface as an indoor thoron source), a homogeneous distribution was expected to be observed for 212Pb activity concentration which was one of thoron progeny. Furthermore, the mean equilibrium factor for thoron obtained by the recent measurements in several countries widely ranged from 0.008 to 0.07. Therefore the bronchial dose evaluated using the equilibrium factor and activity concentration of thoron instead of thoron progeny activity concentration may have a large uncertainty. Thus, the thoron progeny measurement should be investigated at each measurement point for the dose estimation for thoron.
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Affiliation(s)
- Masahiro Hosoda
- Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Hiromi Kudo
- Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Kazuki Iwaoka
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Ryohei Yamada
- Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Takahito Suzuki
- Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Yuki Tamakuma
- Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
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